Ball valves have an actuator, which drives a shaft mounted in a shaft bearing, which transfers the rotation to the valve element which is formed by a ball with a ball passage channel. The components are mounted in a valve housing, and ball valves are considered robust and cost effective and they are used for numerous applications.
In modern refrigerant systems for motor vehicle air conditioners, modern functionalities are increasingly integrated, which are associated with high demands on the individual components of the respective refrigerant system. For example, it is desirable to integrate a heat pump functionality in the design of motor vehicle refrigerant systems. For this purpose, it is necessary to provide the components that are used, particularly the valves and the expansion devices, with expanded functionalities. This leads, among other effects, to the valve being insertable bidirectionally relative to the refrigerant flow through the valve, and to the systems satisfying even particularly high demands in regard to the tightness of refrigerant systems in mobile applications.
To date, hardly any components suitable for practical use are available in the prior art, and consequently proven components have to be modified and adapted to the new challenges.
In the prior art, ball valves according to DE 24 30 409 A1 are known, for example, which are adapted especially as components for fluid line arrangements, so as to satisfy the requirements in regard to tightness and ease of installation as well as optimization of the number of the individual components.
Very generally, ball valves are known to be associated with tightness problems relating to the so-called internal tightness, which concerns the flow of the fluid to be regulated with the valve. The external tightness relates to the tightness of the valve with respect to the environment of the valve, since the moving shaft used for the actuating movement of the valve body has to be sealed with respect to the environment, in order to prevent the discharge of the fluid to be regulated via the rotatably mounted shaft.
In refrigerant systems, additional demands are placed on the valves, since the components also are exposed to very high temperature and pressure differences. In that regard the seals in particular have to be adapted to meet very high demands due to the thermal stresses and the material shrinkage and respectively expansion that occur. Moreover, the problems are exacerbated by the particularly high demands placed on refrigerant-conducting systems used in mobile applications, such as motor vehicles, for example. This is reflected in the expectation of a very long useful life and functional capability of the components in mobile applications, for minimizing the discharge of refrigerant into the environment.
Thus, the aim of the invention is to produce a valve which has a very high tightness in regard to the external seal of the valve with respect to the environment, and which is suitable for use in refrigerant systems for motor vehicle air conditioners.